docs: def file_is_present(self, file_path):
          """
          check if file 'file_path' is present, raises IOError if file_path
          is not a file
  
          :param file_path: str, path to the file
          :return: True if file exists, False if file does not exist
          """
          p = self.p(file_path)
          if not os.path.exists(p):
              return False
          if not os.path.isfile(p):
              raise IOError("%s is not a file" % file_path)
          return True